I think I've sorted this now, but I'm not sure if maybe it works too much now.
When the user's car is created (at start or leaving pits) or reset (including race restarts) or if you take over the car, then the script is run just after the multiplayer packets have been processed.
The car is fully set up by then and assigned to the user, so the script commands work as expected.
I just wondered if it's too much, doing it when the car is reset, or maybe that is what you want.
I'm planning to release another VR test patch today so you could give it a go then.